In this work the effect of crosslinking the enzyme esperase (E.C. 3.4.21.62) and the
proteins bovine serum albumin and casein with the bifunctional compound glutaraldehyde
on molecular mass increase was studied. Two common techniques for measuring molecular
mass of proteins were used: SEC and SDS-PAGE. These techniques revealed that the proteins
bovine albumin and casein, when subjected to chemical crosslinking with glutaraldehyde,
volume fraction 0.25 %, increased their molecular mass by 20- and 40-fold, respectively.
It was also observed that Mr increased proportionally to the increase of glutaraldehyde
concentration in the solution, and that the addition of glutaraldehyde should be
done slowly, in small amounts, in order to attain bigger protein aggregates. When the proteolytic
enzyme esperase was subjected to glutaraldehyde, no increase in its Mr was achieved.
Several assumptions can be made to explain these results, the most reasonable being
the low amount of free lysine groups available for crosslinking. This study confirms that
glutaraldehyde is not an adequate crosslinker for esperase